1. Field of the Invention
The present invention relates to a tone hole pad for a musical wind instrument in which the pad is mounted within a cup for opening or closing a tone hole.
2. Description of the Prior Art
A conventional tone hole pad for a wind instrument is shown in FIGS. 13 to 17, and comprises a circular metal cup 32 including a bottom portion and a wall portion formed on the periphery of the bottom portion. A screw receiver 33 is brazed to the cup 32 (FIG. 15), and a cushion pad 35 and an adjusting paper 36 are mounted in the cup 32. The cushion pad 35 is formed of a thick felt 39 backed by cardboard 40 and wrapped in a pad skin 41, and has a mounting hole 42 formed in the center thereof (FIG. 16). The adjusting paper 36 is first placed on the bottom portion of the cup and the cushion pad 35 is mounted thereon and then fixed by a pad washer 37 and a bolt 38 (FIG. 17). The adjusting paper 36 may regulate the pad""s surface in order to contact with a tone hole""s rim 34 by increasing or decreasing the surface level. The cup 32 mounted with the cushion pad and the adjusting paper is brazed to a lever 31 of a key mechanism provided on the outer surface of a tube body of the instrument.
One of the problems in the prior art tone hole pad is conformability of the cushion pad 35 with the tone hole""s rim 34, i.e. air leaks from a gap produced between the pad""s surface and the tone hole""s rim. A first reason for this is that the screw receiver 33 is liable to be obliquely brazed to the bottom portion of the cup 32. The oblique screw receiver makes the pad washer 37 unevenly press the cushion pad 35 against the bottom portion of the cup 32, and, accordingly, reduces the conformability of the cushion pad 35. In the process of manufacture, in fact it is hard for a worker to braze the screw receiver to the bottom portion of the cup 36 evenly, because it requires a skillful technique. A second reason is the uneven bottom portion of the cup 32. When the cushion pad 35 is pressed by the pad washer 37 against the uneven bottom portion of the cup, the cushion pad is then distorted, whereby a gap is produced between the pad""s surface and the tone hole""s surface and air leaks, even though the adjusting paper lies on the bottom portion of the cup.
A further problem is that tears in the cushion pad""s skin can eventually occur on the portion of the skin that covers the cushion pad. The tears are caused by the pad""s inability to maintain an even tension on the skin during repeated contact with the tone hole surface. Therefore, a pad assembly is needed having components that can provide the necessary support for the pad""s sealing surface and maintain an even tension on the pad""s skin. The deformation of the cushion pad caused by the uneven bottom surface of the cup as described in the previous paragraph is also a cause of tears in the cushion pad""s skin. Replacement of the pad assembly requires the installation of a new pad assembly and adjustment to conform the cushion pad""s surface to the tone hole surface and is both time consuming and expensive.
A further problem is that in the prior art tone hole pad the cushion pad is fixed by a pad washer and bolt in the center. In other words, only the central area of the cushion pad is pressed firmly against the bottom portion of the cup. Accordingly, the pressure of the pad washer is concentrated near the center of the pad so that the outer peripheral portion of the cushion pad is forced to float up and protrude out at an edge of the wall portion of the cup, causing distortion of the cushion pad, and so the pad""s conformability is reduced. Any measures to prevent the outer peripheral portion of the cushion pad""s surface from protruding out at the edge of the cup wall are awaited.
Accordingly, an object of this invention is to provide a tone hole pad for a musical wind instrument that has solved the above problems inherent in the prior art conventional tone hole pad.
To achieve the above object, according to one aspect of this invention, there is provided a tone hole pad for a wind instrument comprising a circular metal cup brazed to a lever of a key mechanism provided on the outer surface of a tube body of the wind instrument, including a bottom portion and an annular wall portion formed on the peripheral portion of the bottom portion. A circular metallic base, which includes a stem portion formed integrally therewith exactly perpendicular to the surface thereof, within which a female screw is formed, is brazed to the bottom portion of the metal cup. The metallic base is formed of a disk-shaped metal plate having a diameter substantially the same as the inside diameter of the wall portion of the metal cup, is provided with a plurality of holes formed at regular intervals between the central stem portion and the peripheral portion of the upper surface thereof, and has a beveled portion formed in a corner portion of the periphery of the rear surface thereof to coincide with a curved portion of the inner peripheral portion of the bottom portion of the metal cup. This beveled portion enables the metallic base to be placed in a proper position in the metal cup.
There is provided a tray-shaped metallic holder having an outside diameter just inside the wall portion of the metal cup and a mounting hole formed in the center thereof. The outer periphery thereof forms a wall portion with a lip which curves inward toward the center thereof. The lip prevents the pad""s surface from floating. Inside the wall portion thereof is formed a ring-shaped concave portion having an outside diameter just inside the wall portion, an inside diameter smaller than the tone hole and an appropriate width and depth to form a space portion into which an elastic resin plate deflects when the tone hole is closed.
A pad assembly is comprised of a felt body formed of a disk-shaped piece of felt, having an upper surface coated with a resin film, a diameter the same as that of the metallic base and a mounting hole formed in the center thereof, and an elastic resin plate formed of a disk-shaped elastic resin plate having the same diameter as of the felt body and a mounting hole formed in the center thereof. The felt body and elastic resin plate are inserted in the metallic holder, which is mounted on the metallic base with the interposition of a circular mount paper formed of disk-shaped cardboard, having the same diameter as that of the felt body and a mounting hole formed in the center thereof, and being fixed by a pad washer and a bolt in the cup.
In accordance with the tone hole pad of the present invention, the following effects and advantages can be achieved.
First, in the process of manufacture, it is easier to settle the metallic base in a proper position in the bottom portion of the metal cup owing to the beveled portion formed in the peripheral portion of the rear surface thereof covering the whole inside rounded portion of the bottom portion of the cup. When the metallic base is brazed to the bottom portion of the cup, a number of the holes perforated between the stem portion and the periphery of the metallic base are of use for a worker through which he can observe with the eye the brazing work and condition on the other surface of the metallic base when it is brazed to the bottom surface of the metal cup. This enhances the work efficiency and contributes to reducing weight.
As a result, a stem portion can be stabilized exactly perpendicular to and in the center of the bottom portion of the metal cup by the existence of the metallic base. Accordingly, the pad assembly can be pressed by a pad washer evenly so as to maintain its surface parallel to the tone hole surface, so that it avoids any risk giving rise to damage to the pad""s surface which causes a gap and air leakage. Accordingly, complete conformability of the pad""s surface with the tone hole can be ensured.
As comprised of the thin felt body, the upper surface of which is coated with the resin film, the elastic resin plate and the mount paper, the pad assembly itself is elastically deformable and restorable. Thus the pad cannot suffer from excessive pressure from the tone hole by a player""s violent touch or uneven pressure by distortion of the tone hole. Also, the space portion in the ring-shaped concave portion provided in the peripheral portion of the upper surface of the metallic holder allows deflection of the elastic resin plate when the tone hole is closed.
Further, the pad according to the present invention is durable for long use, since all the pad components are held by the metallic holder.